I would like to know if anyone has an algorithm or source code for a
program that they would be willing to share which averages two or more
time series collected under the same experimental conditions: e.g.,
several gait cycles or reaches to a target under constrained conditions.
The program would have to run on an IBM-386 compatible computer.

I have some data that I have collected in which the time series of,say,
the knee for the same experimental condition varies from trial to trial;
e.g., 90 samples long on one trial, 92 N on another, etc.
Therefore, I need to normalize the trajectories, interpolating the
time series for the shorter trials, and then average them to get the
mean trajectory and its SD. I have a relatively urgent need to do this
so any help that any of you could provide would be greatly appreciated.